Bryan McAllister’s personal reference notebook
July 30, 2026Short & citedBlog
Civic Viewpoint.
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Field Notes • Biology

Whale shark

The whale shark (*Rhincodon typus*) is the largest living fish and a slow-moving, filter-feeding shark.

Updated July 30, 20261 min readCited sources

The whale shark is the largest living fish and a filter-feeding shark. Despite its size, it is harmless to humans and feeds mainly on tiny organisms.

What it is

The whale shark is a cartilaginous fish and the largest known living fish species. Its huge mouth and filter-feeding anatomy are adapted for straining small prey from seawater.

Where it lives

Whale sharks occur in marine environments worldwide, especially in tropical and warm waters. They are pelagic, meaning they live in the open ocean rather than on the seafloor.

Human interactions and conservation

Whale sharks are generally harmless to people and are often described as gentle giants. The species is considered Endangered, with populations affected by fishing, bycatch and collisions with ships.

In short

  • Largest living fish species.
  • Filter feeder that eats plankton and small organisms.
  • Found in tropical and warm oceans worldwide.
  • Listed as Endangered on the IUCN Red List.
Canadian angle

Whale sharks are of interest to Canadian readers through aquarium and marine-science education, ocean conservation reporting, and global biodiversity discussions, though they are not native to Canadian waters.

Quick questions

What is a whale shark?
A whale shark is the largest living fish species, a slow-moving shark that filters tiny organisms from the water.
How big is a whale shark?
Whale sharks can grow to about 18–20 metres long, with some sources noting verified individuals near 19 metres.
Are whale sharks dangerous to humans?
No. Whale sharks are generally non-aggressive and considered harmless to humans.

Sources

  1. Marine Megafaunahttps://marinemegafauna.org/whale-sharks/facts
    Supports: Largest fish, diet items, harmless to humans, lifespan estimate.
  2. National Geographic Kidshttps://kids.nationalgeographic.com/animals/fish/facts/whale-sharks
    Supports: Scientific name, size context, diet, non-aggressive nature, lifespan estimate.
  3. PBS Naturehttps://www.pbs.org/wnet/nature/blog/whale-shark-fact-sheet/
    Supports: Largest extant fish, size, harmless nature, lifespan estimate.
  4. National Geographichttps://www.nationalgeographic.com/animals/fish/facts/whale-shark
    Supports: Scientific name, size, lifespan, endangered status.
  5. Encyclopaedia Britannicahttps://www.britannica.com/animal/whale-shark
    Supports: Largest living fish, distribution, lifespan range.
  6. Florida Museum of Natural Historyhttps://www.floridamuseum.ufl.edu/discover-fish/species-profiles/whale-shark/
    Supports: Pelagic habitat and maximum size.
  7. Greenpeacehttps://www.greenpeace.org/usa/oceans/wildlife-facts/whale-shark/
    Supports: Global warm-water distribution, diet, lifespan estimate.
  8. Woods Hole Oceanographic Institutionhttps://www.whoi.edu/ocean-learning-hub/ocean-facts/whale-shark/
    Supports: Diet composition and feeding mode.